Explore istanbuls unesco listed old city on this small group 8 hour walking tour admire the opulent topkapi sarayi home of the ottoman sultans hagia sophia once the largest church in all of christendom the 17th century blue mosque and the roman era hippodrome before soaking up the atmosphere of the vibrant grand bazaar please note that tuesday tours exclude topkapi sarayi and substitute yerebatan sarayi basilica cistern and the spice market while the grand bazaar is closed on sunday